In a milestone moment for Patagonian conservation and for one of the world’s great whitewater rafting and kayaking destinations, the Spanish energy company Endesa today, August 30, 2016, relinquished all claims to Chile’s Futaleufú, Puelo, Bardón, Huechún, and Puelo rivers. The damming of the Futaleufú has been the source of an intense environmental lobbying effort for nearly two decades. Outside has covered the story for most of that time, including a 2003 trip when the late David Rakoff joined Robert F. Kennedy Jr. on a float of its iconic green waters.

A statement filed with the Chilean government this afternoon following a board meeting reads in part: “Taking into account the high annual cost for the company to maintain water rights without using them, and that the projects ... were not technically and economically feasible to perform, and did not have the sufficient support from local communities, we’ve decided to waive the rights of water exploitation associated with the hydroelectric projects.”

This comes two years after the company agreed to suspend any immediate plans to dam the Futaleufú, which has one dam near its headwaters in Argentina but flows free for 65 miles through Chile. The announcement called the move a $52-million dollar loss to Endesa shareholders.

“They’re literally just giving up and exiting these watersheds,” says Patrick Lynch, staff attorney and international director at Futaleufu Riverkeeper, a nonprofit offshoot of Robert F. Kennedy Jr.’s Waterkeeper Alliance and one of the organizations that has spent the last two decades fighting to keep the last best Chilean rivers undammed after losing the Bio Bio to an Endesa dam in 1996. Others include the Patagonia Defense Council and the Natural Resources Defense Council.

The exit of Endesa from these rivers leaves a vacuum that must now be filled. In Chile, water rights for power generation are claimed on a first-come basis, which means that any commercial entity can now claim the rights. “One option is we can actually request those water rights ourselves,” says Lynch. A non-profit or coalition of conservation organizations could claim the rights. They’d then have a year to raise the money to pay an annual fine for non-development to the Chilean government while they attempt to change the law to allow for something like a public water trust. These fines get larger over time, gradually topping a million dollars per year, which is one of the reasons Endesa saw a financial incentive to abandoning their rights now instead of throwing good money after bad. On the other hand, the rights are also now free for another hydroelectric company to claim. China, the world’s leader in dam building, would be the most likely international suitor. But it’s a risky business trying to build dams in a country whose populace clearly thinks they’ve got enough of them.